Method of and apparatus for surfacing pavements



J. E. LOFT 2,152,264

METHOD OF AND APPARATUS FOR SURFACING PAVEMENTS March 28, 1939.

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' METHOD OF AND APPARATUS FOR SURFACING PAVEMENTS Filed May 27, 1937 v 2 Sheets-Sheet 2 Patented Mar. 28, 1939 UNITED STATES LETHOD OF AND APPARATUS FOR SURFACING PAVEMENTS John E. Loft, Worcester, Mass.

Application May 27, 1937, Serial No. 145,146

14 Claims.

The principal objects of this invention are to provide for improving pavements by surfacing them by means of one machine, eliminating the cost of finishers and other men to follow the machine and smoothing out the irregularities which are produced in the pavement; to provide for surfacing practically dry concrete which cannot be surfaced by screeding; to provide an improved pavement in which there is a layer of large stones arranged along the top of the pavement with a covering of fine concrete, or, in some cases, bituminous material, over them; to provide a pavement in which the scaling of the surface will be reduced; to provide a machine for accomplishing the above mentioned results involving a carriage movable along the forms slowly and constantly, combined with aframe supported by that carriage and carrying rollers, with means for reciprocating the frame on the carriage so that the rollers will pass back and forth rapidly but progressively along the pavement; to provide a combination of corrugated main rollers followed by a smoothing roller, all connected with, and drawn along with, said frame; to provide a machine for the above mentioned purpose in which the said corrugated rollers are formed with interstices between the corrugations through which the finer parts of the cement can pass upwardly to leave a fine surface on the pavement and leave the large stones below said fine surface; to provide the so-called corrugated rollers in the form of skeleton hollow cylindrical rolls formed of a pair of discs and bars extending across from one disc to the other in a slanting position; to performthe operation by means of these rollers in which the bars of the rollers are slanted in opposite directions; to provide means on the frame itself for reciprocating the frame with its rollers on the carriage which travels uniformly in one direction; to provide means in connection with the support of the rollers on the frame by which the rollers can be caused either to roll the grade below the tops of the forms or to roll the final surface substantially at the top of the forms, and to provide means moving with the frame for forming a narrow space along each side of'the pavement at the top and to thereafter round over the edge of the pavement, using this space to receive the excess concrete.

Other objects and advantages of the invention will appear hereinafter.

Reference is to be had to the accompanying drawings, in which I Fig. 1 is a plan of a preferred form of machine for carrying out the method above identified, constituting a preferred form of the apparatus; r

Fig. 2 is a side view thereof;

Fig. 3 is a sectional view of the pavement and I supporting parts for the rollers, showing one of the rollers in elevation;

Fig. 4 is a sectional View on the line 44 of Fig. 3;

Fig. 5 is a sectional view of the forms and the concrete before being treated by this process;

Fig. 6 is a similar View of the same, showing it after being rolled by the skeleton rollers;

Fig. 7 is a similarview of the pavement after the skeleton rollers have just passed; 7

Fig. 8 is an enlarged side view of the form, carriage, and frame showing the rollers blocked up to cause it to roll the concrete to the form shown in Fig. 6;

Fig. 9 is a sectional view on the line 99 of Fig. 6, constituting a longitudinal section;

Fig. 10' is a view similar to Fig. 7 showing the completion of the pavement;

Fig. 11 is an end view of a preferred form of finishing roller;

Fig. 12 is a sectional View of a pavement showing it having been rolled to a sub-grade;

Fig. 13 is a view similar to Fig. 8 but showing the roller supported so as to roll the sub-grade shown in Fig. 12, and

Figs. 14 and 15 are sectional views similar to Fig, 4 showing modified forms of roller bars.

It is well known that on many forms of pavement there is a surface layer which is of a different fineness from the layer below. This surface layer flakes off in many highways, one of the reasons being apparently that, being of a. different material, it has a different coefficient of expansion. This, in itself, would naturally result in some of the flaking under the various conditions under which the highway is used. It is also well known that in laying the concrete it is mixed comparatively wet and that this also may be responsible for some of the flaking.

In accordance with this invention the concrete is laid in a comparatively hard and dry state, so dry in fact that it cannot be tamped with any advantage. This invention has to do with the treatment of such a concrete so as to bring a little moisture to the top, set up vibrations, and produce a fine surfaced layer which will have less tendency to flake than the old forms of concrete highways. It is to be understood, however, that this invention is applicable to certain forms of roads and highways which have a bituminous upper layer. pavement.

For the purpose of this invention a concrete pavement, or one having a bituminous surface, is deposited in the first place, as shown in Fig. 5, with a layer of comparatively large stones l0 along the top thereof in the forms II. A pair of guide plates [2 are shown in this figure, the purpose of which will appear later. According to this method, this concrete or the like deposited in the forms is operated upon progressively by a rolling operation in such a way as to force the top layer of stones I0 down below the surface and to bring an integralfine surface [3 to the top over and around these stones. Afterwards, the guide plates l2 are removed, leaving two edge grooves I4 along the pavement in the forms and the corners at l5 are rounded down to form a chamfered edge on each side. The

It is not limited to an all concrete excess material is received in the grooves l4 so. that it will not be forced out above the top'of the form to forms. ragged edge.

The operation by which these results are secured is performed by. means of a traveling frame l6, which moves forward constantly under any desired motive power, not shown, but at a slow rate of speed, and a carriage I! supported by wheels [8 on the'traveling frame l6 which itself is supported by wheels [9 on the top edge of the frame II. A motive power is carried by the traveling frame in the form of a motor 20 or the like having a crank 2| connected by a link 22 with the carriage l1. The carriage reciprocates at about ten R. P. M. and moves forward progressively as the traveling frame moves along. In other words, the carriage moves back and forth at a comparatively rapid rate and by the movement of the traveling frame it progresses from one end of the pavement to the other.

On this carriage are carried hollow skeleton rollers 24. These are formed by discs 25 at each end and bars 26 secured to and connecting these discs. In the preferred form these bars are shown as cylindrical and as welded to the discs 25. They are shown as slanting, the bars on one roll slanting in one direction and those on the other slanting in the opposite direction. As these bars are slanted and spaced equally apart, it will be obvious that at the central point, between the ends of these rollers, the operative surfaces of these bars constitute a smaller circle than they do at the ends. Therefore, the result is a slight crowning of the surface of the pavement. At the same time they are heavy rollers, which are arranged to penetrate the surface of the pavement, engage the stones l0 near the top and force the top layer of them down below the surface of the pavement. This is possible because the spaces between the bars allow the fine mixture to move up above the stones which had moved down, leaving the surface l3, which has been described.

The rollers 24 are carried along by the carriage and they have central studs 28 projecting through vertical slots 29 in the sides of the carriage. Therefore, they can move up and down in the carriage. These slots are so located on the carriage that when the studs29 are free to move to the bottom of the slots, as shown in Fig. 13, the surfaces of the rolls extending down below the top of the guide frame H, roll the sub-grade, as shown in Fig. '12. The preferred procedure, however, is to place blocks 38 in the bottoms of these slots 29 so as to hold the rolls above or at the top of the guide form. That is. the way the pavement is produced, as shown in Figs. 5, 6,

7, 9 and 10. The surface of this pavement is not smooth but, as shown in Fig. 9, it is broken up by small grooves due to the action of the bars 26.

The guides I2 which are carried with the traveling frame, of course, move along out of the grooves M which they have formed, leaving the pavement shown in Fig. 7 with these grooves present. For the purpose of finishing the surface of the pavement so that no belting or brooming will be required afterwards'and the time for the men employed for this purpose will be saved, a smoothing roll 3| is used. It is connected with the rear of the carriage I! by a pivoted frame 32 having a counterbalance weight 33 behind this roll. This forces the roll down so that it can perform a smoothing operation. However, of course, it is not desired that the pavement shall be absolutely smooth. Therefore, for ordinary pavements, this smoothing roll 3| is provided with irregular and small corrugations 34. These corrugations are also irregularly spaced to avoid the repetition of transverse grooves of the same size and form and yet provide enough roughness to avoid a non-skidding surface. This roll 3| is provided with these grooves throughout its length and it is slightly concaved to fit the crowned surface shown in Figs. 6 and 7. It is also provided with a flange 35 at each end having a smooth concave inner surface 36 and a perfectly flat outer surface. This is for the purpose of forming the chamfer at l5 and pushing the concrete or bituminous material so compressed into the groove I4, leaving the pavement in the form shown in Fig. 10.

The main roller is shown in Fig. 4 as having cylindrical bars 26. The same result is secured by making operative surfaces of the bars 36 semicylindrical, as shown in Fig. 14, or even pointed, as shown at 31 in Fig. 15.

In the operation of this machine and method, the concrete, in a drier state than is considered proper under previous methods, is fed into a hopper 38 carried along the tops of the guide frame II. The hopper is connected by bolting or the like to'the traveling frame IS in front of it. This hopper is filled with the concrete in the usual manner and a gate 40 is employed to regulate the fiow of concrete into position between the forms. Just behind this gate is located an adjustable plow 4| for preliminarily smoothing the surface of the concrete. As stated, this concrete is mixed'to a comparatively dry state, so dry that it could not be tamped and a layer of stones I0 is left at the top. As the traveling frame moves forward, the rolls 24 roll the big stones down below the surface and allow the fine concrete to move up above the bars 26 and fall back into a. thin layer l3 on top. The smoothing roll follows them and performs the operation, previously described, of finishing the pavement.

In this way a pavement is secured in which the top surface I3 is formed integrally with the section of pavement just below it, which contains a horizontal layer of comparatively large stones, affording a maximum of strength at this point. The top is slightly crown and made with a slightly rough and irregular surface and the edges are chamfered without necessitating the running of the concrete over the edges in order to do that. The number of men employed is reduced and therefore the cost of operation.

Having thusdescribed my invention and the advantages thereof, I do not wish to be limited to the details herein disclosed, otherwise than as set forth in the claims, but what I claim is:

1. The methodof surfacing a concrete pavement, which comprises distributing concrete in a nearly dry state, rolling back and forth over the surface thereof a heavy skeleton rollhaving bars extending along it adapted to sink into the surface of the concrete and force the top of the concrete upwardly through spaces between said bars and force the stone in the concrete down below the surface thereof, smoothing the concrete surface, forming a longitudinal groove along each side of the pavement during the rolling operation, and, while smoothing the pavement, rounding off each edge, and forcing the excess concrete into said groove.

2. A device for compressing a pavement and forming the top surface thereof comprising a pair of skeleton rollers formed of a pair of end discs and a series of parallel substantially longitudinal bars extending from one disc to the other, said bars having surfaces for projecting into the upper surface of the pavement.

3. A device for compressing a pavement and forming the top surface thereof comprising a frame adapted to travel along the surface of a pair of forms and to rest thereon, a carriage resting on said frame and movable back and forth thereon, and skeleton rollers supported by said carriage, each formed of a pair of end discs and bars extending across from one end disc to the other and spaced apart.

4. A device for compressing a pavement and forming the top surface thereof comprising a pair of skeleton rollers formed of a pair of end discs and a series of parallel bars extending from one disc to the other, said bars having surfaces for projecting into the upper surface of the pavement, a frame adapted to travel along the surface of a pair of forms and to rest thereon, a carriage resting on said frame and movable back and forth thereon, said carriage being provided with said skeleton rollers, the bars of each roller being located in a slanting position and those of each two adjacent rollers having their slanting directions alternate.

5. A road surfacing machine comprising a traveling frame having rollers for resting on a pair of forms and carrying the frame, a carriage having rollers supported on said traveling frame, means for moving said carriage back and forth horizontally on the frame, and rollers carried by said carriage and capable of moving up and down, said rollers comprising operating surfaces formed of spaced bars extending from one end to the other.

6. A road surfacing machine comprising a frame adapted to travel along the forms for supporting the sides of the road bed during its consolidation, a carriage having rollers resting on the frame and supported thereby, means for moving the carriage back and forth as the frame moves forward, the sides of the carriage having opposite vertical slots, and rollers carried between the sides of the carriage and each having a stud projecting into one of said slots, whereby the rollers are capable of moving up and down in the slots.

7. A road surfacing machine comprising a frame adapted to travel along the forms for supporting the sides of the road bed during its consolidation, a carriage having rollers resting on the frame and supported thereby, means for moving the carriage back and forth as the frame moves forward, the sides of the carriage having vertical slots, rollers carried between the sides of 3- the carriage and each having a stud projecting into one-of said slots whereby the rollers are capable of; moving up and down in the slots, said slotsbeing deep enough to allow the rollers to project down below the tops of the forms to enable the machine to roll-a sub-grade, and blocks adapted toput into saidslotstohold the rollers in a position to roll the pavement at the top of the forms.

a 8- In a road surfacing machine, the combination: of the forms of the pavement with a traveling frame supported thereby, a carriage supported by the traveling frame, means for moving the carriage back and forth as the frame moves constantly forward, and rollers on the carriage, each roller being formed with straight bars located at an inclination on the surface thereof and spaced from each other, whereby the rollers will produce a slightly crowned pavement.

9. In a surfacing machine for pavements, the combination with guide forms, of a frame adapted to travel along the guide forms constantly, a carriage capable of being reciprocated on the frame, and rollers constituting a part of the carriage and capable of moving up and down therein and having projecting surfaces for forcing the top layer of stones down below the top of the pavement and having spaces between and through said surfaces for allowing the fine part of the pavement to project up through them.

10. A device for compressing a pavement and forming the top surface thereof comprising a frame adapted to travel along the surface of a pair of forms and to rest thereon, and a carriage having rollers resting on said frame and movable back and forth thereon, skeleton rollers carried by the carriage, each roller formed of a pair of end discs and bars extending across from one end disc to the other and spaced apart, the bars of each roller being located in a slanting position and those of two adjacent rollers having their slanting directions alternate, and a smoothing roller pivotally connected with the rear of said carriage and resting on the surface produced by rollers, said smoothing roller having an irregularly corrugated surface and being slightly concave from end to end, and a counterweight carried with the smoothing roller to force it into the rolled surface.

11. A device for compressing a pavement and forming the top surface thereof comprising a frame adapted to travel along the surface of a pair of forms and to rest thereon, and a carriage having rollers resting on said frame and movable back and forth thereon, skeleton rollers movable with said carriage, each formed of a pair of end discs and bars extending across from one end disc to the other and spaced apart, and a smoothing roller acting by gravity on the surface of the pavement and connected with said carriage by moving therewith.

12. In a surfacing machine for pavements, the combination with guide forms, of a frame adapted to travel along the guide'forms constantly, a carriage reciprocable on the guide forms, rollers constituting a part of the carriage and capable of moving up and down therein and having projecting surfaces for forcing the top layer of stones down below the top of the pavement and having spaces between said surfaces for allowing the fine part of the pavement to project up through them, strips carried by the bottom of said traveling frame at the edges of the pavement and projecting down below the top of the pavement to form ing from one disc to the other and spaced apart throughout their length. j

14. As an article of manufacture, a roller for rolling and smoothing the surface of a. pavement, comprising a disc ateach end, a central stud constituting a trunnion on each disc, and a series of convex sided bars secured to the edges of the discs in a circular manner and extending from one disc to the other in a slanting direction and spaced apart.

JOHN E. LOFT. 

